As far as power failures go, few can match the dubious record set by Brazil last year. On the night of 10 November, nearly 70 million people were left in the dark some of them for up to five hours in an incident that is still being investigated by national authorities. The massive blackout affected not only 18 of Brazil's 27 states, but also the entire population of Paraguay. Sao Paulo and Rio de Janeiro, Brazil's two largest urban areas, were among hundreds of cities and towns that were unexpectedly plunged into darkness.